My ISP provides Junk Email protection and it does actually do a good job at this and marks all junk messages with ***SPAM***. Is there any way I can tell Outlook not to download these mails?
Not really, since this is not something that you have to do in Outlook but which you can do in the web based mailbox of your ISP.
Most likely you’ll also have the option in your web based mailbox what to do with junk emails. Common options are;
- mark them (like ***SPAM***)
- move them to a folder
- move them to the Deleted Items folder
- delete them permanently
Usually you can combine the "mark them" option with the "move" or "delete" option. Sometimes the "move" and "delete" option are only available in the message rules. In that case you can create a rule to move/delete the messages when it has ***SPAM*** in the subject.
Since a POP3 account can only download from the Inbox folder, moving your junk email messages out of it will prevent Outlook from being able to download already identified junk email.
Note: If you choose to keep the ***SPAM*** messages, you’ll need to login to your web based mailbox every now and then to review and clear the folder to prevent your mailbox from becoming full. Some web based mailboxes provide the option to automatically clear some folders after x number of days to prevent this too. Consult the documentation of your ISP or contact them to find out which options are available to you.